Strengthening Immunization Systems through Serosurveillance (SISS)

The challenge

Sero-epidemiology is a potentially powerful tool to measure population immunity to vaccine-preventable diseases, identify immunity gaps, and guide immunization activities. However, there is a need to evaluate how to design, implement and evaluate serological surveillance systems and make the best use of the data to guide vaccination programs and policy. The SISS project addresses epidemiological, technical, and operational issues critical to the generation and interpretation of valid and timely serological data to identify immunity gaps and guide routine, supplemental and targeted immunization activities.

Approach

Multiple measles and rubella serosurveys were conducted in India and Zambia to demonstrate the feasibility and utility of serological surveillance to guide immunization programs. In India, measles and rubella serosurveys were conducted before and after mass vaccination campaigns in four districts to document increases in population immunity and remaining immunity gaps. In Zambia, measles and rubella serosurveys leveraged a national biorepository and were nested within post-coverage evaluation surveys, measles and rubella SIAs, and the fever/rash surveillance system. Comparisons between seroprevalence estimates obtained from community-based surveys and residual specimens from health care facilities and laboratories were done in both countries.